Ceramic matrix composites (CMC) have an advantage over polymeric matrix composites because of their high-temperature performance. The mechanical properties of these composites are critical for both material researchers and modeling engineers to evaluate material performance. One of the properties of interest is the through-thickness modulus of the composites. For thick composites, i.e., about 20 mm thickness, this modulus may be estimated by mechanical testing. However, most CMCs are thin, i.e., about 2 mm; thus measuring through-thickness properties by conventional mechanical methods is difficult and results in destruction of the specimen. Other mechanical test methods have been proposed, such as stacking multiple CMC panels together and testing them in compression.
Ultrasonic non-destructive evaluation (NDE) may provide the ability to measure through-thickness modulus needed for modeling support. However, typical ultrasonic studies on composites are conducted by immersing the specimen in a water tank and often requires a complicated inversion process to derive elastic constants from the ultrasonic amplitude data. For non-immersion tests or contact ultrasonic methods, elastic constants can be measured directly by the ultrasonic bulk wave velocity, but a disadvantage of this approach is that it requires multiple specimens of different orientations. Modulus evaluations of materials, if feasible, are typically performed in a tensile test machine which requires destruction of the specimen from which the material is received. Accordingly, such materials and the specimen are no longer able to be used.